how to calculate the radius of an image more irregular if I know the centroid?

Hello everyone! I have a small question and would appreciate if someone could help me. I'm working with a picture of a mole, I know the centroid of the image, and I'd like to know which is the major radius of the image. Anyone know how to do? thank you very much

[Sean de Wolski]

Please provide a link to an example image and the code you are currently using.

Answer 1

[Image Analyst]

Use regionprops and ask for the EquivDiameter. That is the diameter as if the blob were perfectly circular with the same area. See my image segmentation tutorial for more info. http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

[elena]

I'm using regionprops and see the result of equivalent diameter, but I have a problem, I'm working with a color image that I converted to white and black and filled the holes but there is noise, then regionprops returns multiple values for each of the fields. Is there any way to get only the value of the diameter for the image discarding the rest, without having to do it manually? Or some other way to get the largest diameter without using regionprops?

[Image Analyst]

Try bwarea() to get rid of small noise blobs. Otherwise upload your image so I can take a look at it.

Answer 2

[David Sanchez]

Are you using the function regionprops ?

[elena]

I try it with regionprops calculating the AxisMajorLength but do not really understand the operation and does not give me the results I am looking for. Is there another way to do it?